Unfortunate about the maintainer of core-js. But how does that make Babel shady? Especially if they made the change before asking for money.
Sounds more like they were struggling with workload and made what, at the time, seemed like a reasonable decision to offload some of the work to another library.
Also the core-js maintainer single handedly carried that project, with no financial support from Babel (or hardly anyone else for that matter). It became a vital part of the ecosystem, and then the community hung him out to dry when he asked for more support. The whole thing was shameful, especially those who mocked him for his unfortunate personal situation.
